A sore throat occurs when the throat is inflamed. It can be caused by viruses, bacteria, allergens/irritants, or injuries.
Most cases of the sore throat are caused by viruses, including the viruses that cause the common cold, flu, mononucleosis (mono or the “kissing disease”), measles, and chickenpox.
Though less common, sore throats may also be caused by bacteria including bacteria that cause strep throat, inflammation of the tonsils, and diphtheria. Allergens or irritants such as pollen, pet dander, and acid from the stomach going back up the throat (GERD) can also cause sore throat. Excessive screaming can also injure the throat and result in a sore throat.